Optical disk drive unit with a sealing type bearing member

ABSTRACT

An optical disk drive unit comprising: a sealing enclosure which encloses from exterior the disk cartridge and an access mechanism for the recording medium in the disk cartridge; an input device for inputting an eject command signal; a pin for moving and arranging a cartridge eject device to a state for starting its function; a cam which is disengaged from the pin when the cartridge is unloaded and which is contacted from the pin to start the ejecting function when the cartridge is loaded so that by rotating the cam, the ejecting function can be conducted; a cam drive disposed outside of the enclosure; a linkage for connecting a shaft of the cam drive to the cam through a hole formed in the enclosure; and a controller for controlling the cam in such a way that upon receipt of the eject command signal from the input device, the cam drive is driven to rotate the cam until the cartridge is ejected, wherein through a hole  15  of the chassis  1  is inserted a shaft  81  of the cam  80,  and a worm wheel  79  is connected to the shaft  81  through an engagement member  82,  the worm wheel  79  engaging with a worm  77  installed on a rotational shaft of an eject motor  76.

This is a continuation of application Ser. No. 08/514,225 filed Aug. 11,1995, now abandoned, which is a re-issue application of Ser. No.07/890,539 filed May 28, 1992, now U.S. Pat. No. 5,301,179.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an optical disk drive unit having amechanism for loading a disk cartridge which houses a disk-shapedrecording medium on the device at a predetermined position thereof andejecting the loaded disk cartridge from the device as well.

2. Description of the Related Art

An optical disk device uses an optical disk or a magneto-optic disk as arecording medium. The device uses the optical disk or magneto-optic disk(which is simply referred to as optical disk hereinafter) in a statewherein the optical disk is housed in a disk cartridge so that theoptical disk can be conveniently exchanged.

Such a medium interchangeable optical disk device comprises a loadingmechanism and an ejection mechanism for exchanging the disk cartridge,which forms many opening portions through which the inside of the devicecommunicates with the outside of the device on the housing or chassis ofthe device so that the outer air is freely introduced into the device.

Accordingly, dusts or other particles included in the air stick to theoptical parts assembled in the pickup device, which disturbs thewave-form of the optical signal, which lowers the reliability of thesignal and causes the data error.

In order to prevent the outer air from entering into the optical diskdevice, it may be ideal to completely enclose the optical disk device.

However, in accordance with the ejection mechanism of the related art,to set the ejection mechanism as the initial state thereof, before theoperation of the optical disk device, an eject pin has to be moved to apredetermined initial position by manually pressing an eject button, forinstance. For this purpose, the chassis of the optical disk drive unitof the related art has a longitudinal opening formed thereincorresponding to the moving range of the eject pin, which involves inthe problem of entrance of outer air into the device through theopening.

Also, the movement of the eject pin along the longitudinal openingcauses to generate dusts which are introduced into the device andattached to parts installed in the device.

SUMMARY OF THE INVENTION

The present invention was made considering the above mentioned problemsof the related art. It is therefore an object of the present inventionto provide an optical disk drive unit which is able to prevent theentrance of dusts into the optical disk device through the openingaround the eject pin and avoid generation of dusts due to the movementof the eject pin.

The above mentioned object of the present invention can be achieved by

an optical disk drive unit for loading a disk cartridge which houses adisk-shaped recording medium at a predetermined position in the unit andejecting the loaded disk cartridge from the unit as well, the opticaldisk drive unit comprising:

a sealing enclosure which sealingly encloses the recording medium and anaccess mechanism for writing/reading data on and from the recordingmedium from exterior in a state where the disk cartridge is installed inthe unit;

an input device for inputting a command signal to eject the loaded diskcartridge from the unit;

an eject device for ejecting the disk cartridge from the unit;

a pin for moving and arranging the eject device to a state for startingits ejecting function;

a cam member which is arranged in such a way that the cam member is in astate of being disengaged from the pin when the disk cartridge is beingunloaded from the unit and that the cam member is in a state of beingcontacted from the pin to start the ejecting function by the ejectdevice when the disk cartridge is being loaded in the unit so that byrotating the cam member, the ejecting function can be conducted;

a cam drive device for driving the cam member to rotate which drivedevice is disposed outside of the sealing enclosure;

a linkage device for connecting a rotational shaft of the cam drivedevice to the cam member which linkage device is disposed penetratingthrough a hole formed in the sealing enclosure; and

a control device for controlling the cam member in such a way that uponreceipt of the command signal to eject the disk cartridge transmittedfrom the input device, the cam drive device is driven to rotate the cammember until the disk cartridge is ejected.

An advantage of the present invention is that, due to the arrangementwherein the drive unit for driving the eject pin is disposed in theoutside of the enclosure body, it becomes possible to prevent dusts fromentering into the enclosure which dusts are generated from the drivemechanism.

Also, it is another advantage of the present invention that, due to thearrangement wherein the opening around the linkage member which linksthe cam member and the drive unit together is closed, it becomespossible to avoid entrance of dusts through the opening.

Further objects and advantages of the present invention will be apparentfrom the following description of the preferred embodiments of theinvention as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is an exploded perspective view of the magneto-optic disk driveunit in accordance with an embodiment of the present invention;

FIG. 1b is a sectional view of the cam which constitutes a disk loadingmechanism of the present invention;

FIG. 2a is a perspective view of an example of the disk cartridge inaccordance with the present invention;

FIG. 2b is a partial perspective view of the disk cartridge of FIG. 2a;

FIG. 3 is a plan view of the latch mechanism for explaining the functionthereof;

FIG. 4 is a side view of the carrier and tray combined together;

FIG. 5a is a partial exploded perspective view of an example of theeject mechanism in accordance with the present invention;

FIG. 5b is a partial sectional view of the eject mechanism of FIG. 5a;

FIGS. 6a to 6d are explanatory views for explaining the function of thecam member in accordance with the present invention;

FIG. 7 is an exploded perspective view of an example of the enclosurehosing body structure in accordance with the present invention;

FIG. 8 is a schematic partial sectional view representing a state wherethe chassis and the chassis cover are combined together;

FIG. 9 is a perspective view of an example of the access mechanismhoused in the chassis in accordance with the present invention;

FIG. 10 is a sectional view of the optical disk drive unit in a statewherein the disk cartridge is sealingly enclosed therein;

FIG. 11 is a block diagram of the control system applied to themagneto-optic disk device in accordance with the present invention;

FIG. 12 is a flow chart of an example of the process of the ejectingfunction in accordance with the present invention;

FIG. 13a is a partial sectional view of another example of the sealingstructure for the eject mechanism in accordance with the presentinvention;

FIG. 13b is a partial sectional view of still another example of thesealing structure for the eject mechanism in accordance with the presentinvention; and

FIG. 13c is a partial sectional view of a further example of the sealingstructure for the eject mechanism in accordance with the presentinvention.

FIG. 14a is a partially expanded perspective view of another example ofthe eject mechanism in accordance with the present invention;

FIG. 14b is a schematic view showing a movement of the worm wheel 79seen from the bottom thereof, in the eject mechanism of FIG. 14a;

FIG. 14c is another plane view of the male engagement member 82 used inthe eject mechanism of FIG. 14a;

FIG. 15 is an explanatory view of the cam member used in the opticaldisk drive unit in accordance with the present invention, in which anincreasing ratio of a radius to a rotary angle of the cam member is notconstant;

FIG. 16a is a graph showing a change of the radius value of the cammember 80, with respect to the rotary angle thereof;

FIG. 16b is a graph showing a change of the current value flowing in amotor, with respect to the rotary angle of the cam member 80;

FIG. 16c is a graph showing a change of the radius value of the cammember 80 of FIG. 15, with respect to the rotary angle thereof; and

FIG. 16d is a graph showing a change of the current value flowing in themotor, with respect to the rotary angle of the cam member 80 of FIG. 15.

FIG. 16e is a view of an example for showing a change of the load of thesimplified loading system with respect to a loading stroke.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are described hereinafter in detailwith reference to the drawings.

FIG. 1a illustrates the magneto-optic disk drive unit in accordance withan embodiment of the present invention.

In the drawing, the magneto-optic disk drive unit comprises a chassis 1on which is mounted a disk loading mechanism constituted from a tray 2for housing a disk cartridge (described later), a carrier 3 whichreciprocates in the directions of insertion and ejection for the diskcartridge, and cams 4, 5, 6 and 7 which links the tray 2 and the carrier3 with each other so that the tray 2 is moved back and forth in thedirections of insertion and ejection of the disk cartridge along withthe movement of the carrier 3.

In the chassis 1, there are disposed leveling pins 8, 9, 10 and 11 forstandardizing the height of the disk cartridge which is to be installedin the disk drive unit. The disk cartridge is inserted into the driveunit from the front side of the unit in the drawing. Two of the levelingpins 9 and 11 are disposed back and forth on the right side of thechassis 1 with respect to the cartridge insertion direction. The carrier3 has longitudinal holes 12 and 13 formed therein along the insertiondirection of the disk cartridge for guiding the pins 9 and 11 arrangedon the chassis 1.

At a portion in front of the front side hole 12 of the carrier 3 isarranged an eject pin 14 disposed underside of the carrier 3 protrudingdownward therefrom. The eject pin 14 is arranged to push the carrier 3in the operation of ejecting the disk cartridge. The chassis 1 has ahole 15 formed therein through which an eject mechanism (describedlater) for driving the eject pin 14 is arranged to pass.

Pins 16 and 17 are disposed behind the leveling pins 8 and 9,respectively. The carrier 3 has longitudinal holes 18 and 19 formedtherein through which the pins 16 and 17 of the chassis 1 are guided andescaped, respectively, so that the pins 16 and 17 protrude through theholes 18 and 19, respectively, toward the upper side of the carrier 3.Hooks 20 and 21 are arranged in the rear side portion of the carrier 3.Springs 22 and 23 which bias the carrier 3 to move toward the cartridgeejecting direction are disposed spanning between each of the hooks 20,21 and each of the pins 16, 17 protruding through the holes 18, 19,respectively.

When the disk cartridge is not installed in the carrier 3, the biasforce from the springs 22 and 23 is made unenforceable on the carrier 3due to the arrangement of a latch mechanism 24 which is disposed behindthe hole 13 of the carrier 3 and prevents the carrier from moving.

The latch mechanism 24 comprises an axle 24a arranged on the chassis 1,a latch plate 24b rotatably attached to the axle 24a, a latch pin 24cmounted on the latch plate 24b at a position where the pin 24c is ableto engage with a lever 25 attached to the tray 2, a latch roller 24ewhich is arranged to engage with a recessed portion 24d formed in thecarrier 3, and a latch spring 24f made from a coil spring biasing thelatch plate 24b in the direction where the pin 24c comes in contact withthe lever 25. An end of the spring 24f engages with an end of the plate24b and the other end of the spring 24f engages with a pin 24g disposedadjacent to the axle 24a.

Along the both side edges of the carrier 3, at the front and rear endportions thereof, four vertically rising pieces 26, 27, 28 and 29 areformed. A cam 4, 5, 6, 7 is arranged corresponding to each of the pieces26, 27, 28 and 29 in such a way that a functioning axle 4a, 5a, 6a, 7aof the cam 4, 5, 6, 7 is inserted into a through-hole formed in eachpiece 26, 27, 28, 29. The cam 4, 5, 6, 7 has another functioning axle4b, 5b, 6b, 7b formed on the same side as the axle 4a, 5a, 6a, 7a. Eachaxle 4b, 5b, 6b, 7b is inserted into a through-hole 30, 31, 32, 33formed in each of both side walls of the tray 2. It is to be noted thatthe holes 31 and 33 are desirably formed as an oval hole to absorb theunevenness of the assembling accuracy of the cam.

The cam 4, 5, 6, 7 has a pivot axle 4c, 5c, 6c, 7c formed on the otherside of the functioning axle side, as illustrated in FIG. 1b which isrepresenting only the cam 4 but the same as for the other cams 5, 6 and7. The pivot axle 4c, 5c, 6c, 7c is inserted into each of through-holes1c, 1d, 1e and 1f formed in side plates 1a and 1b vertically disposedalong both of the right and left side edges of the chassis 1.

In accordance with the arrangement mentioned above, the cams 4, 5, 6 and7 are rotatably attached to the chassis 1 and interconnect the tray 2and carrier 3 as well. Also, due to this arrangement, the movementdirection of the tray 2 is limited to the direction which is allowed bythe cams 4, 5, 6 and 7.

Also, at the root portion of each pivot axle 4c, 5c, 6c, 7c of the cam4, 5, 6, 7 is formed a hub 4d, 5d, 6d, 7d protruding from the cam disksurface, as illustrated in FIG. 1b, so as to decrease the contact areabetween the cam and the chassis aiming at reduction of the frictionalforce generated therebetween. Further, the cam 4, 5, 6, 7 is made fromresin having a low frictional coefficient such as polyacetal so as tominimize the frictional force generated in the contact area between thecam and the chassis.

The tray 2 is formed in such a shape that the tray holds the diskcartridge from upper side and the both right and left sides thereof.Also, the tray 2 has a support rim member along each of the right andleft side edges of the tray at the lower portion thereof. The inletportion for the cartridge of the rim member of the tray 2 is crankeddownward.

Inside of the tray 2, two levers 25 and 34 are rotatably arranged toopen and close a shutter of the disk cartridge as described later. Thelevers 25 and 34 are biased outward. A guide pin or engaging hook 35, 36is disposed on the upper surface of each of the levers 25 and 34. Theguide pins (hooks) 35 and 36 are inserted in circular arc shaped guideslots 37 and 38 formed in the upper plate member of the tray 2,respectively, engaging with the rim of each slot opening. The hooks 35and 36 are guided along the slots 37 and 38, respectively, whereby themovement directions of the levers 25 and 34 are limited. Also, thelevers 25 and 34 are disposed at different levels so that they can movewithout interfering with each other.

In the lever 25 is formed a longitudinal hole 38 through which the latchpin 24c penetrates. Also, a cut away 39 is formed in the lever 25opening the hole 38 out of the lever 25 so as to guide the latch pin 24cinto and out of the hole 38.

On the upper surface of the tray 2 is mounted a magnetic head 40 forgenerating an auxiliary magnetic field within a movable range of theoptical pickup. Also, inside of the tray 2, along the both right andleft side edges of the tray 2, pressing strip members 41 and 42 arearranged to limit the height of the disk cartridge by pressing thecartridge from upper side thereof. The pressing members 41 and 42 arebiased downward by leaf springs 43 and 44, respectively. Only one of theleaf springs 43 is illustrated in FIG. 1a.

FIGS. 2a and 2b illustrate an example of the disk cartridge which isdriven by the drive unit in accordance with the present invention.

As illustrated in FIG. 2a, in the center portion of the disk cartridge55 is formed a rectangular access window 56 which is longitudinal in theinsertion direction of the cartridge. The window 56 is opened and closedby a shutter 57. The shutter 57 is arranged as being folded from an edgeportion 60 of the cartridge 55.

The shutter 57 arranged as mentioned above has openings 58 and 59 forreceiving the above mentioned levers 25 and 34, respectively.

In accordance with the above mentioned structure, in the event whereinthe disk cartridge 55 is not housed in the tray 2, as illustrated bydash-two-dot lines in FIG. 3, the latch roller 24e of the latchmechanism 24 is being caught in the recess 24d of the carrier 3.Thereby, the eject springs 22 and 23 are made unenforceable to thecarrier 3.

Also, in this state, the carrier 3 is waiting for insertion of thecartridge at the rearmost position with respect to the insertiondirection. Therefore, as illustrated by solid lines in FIG. 4, the axles4b, 5b, 6b and 7b of the cams 4, 5, 6 and 7 are being positioned at theuppermost level thereof. Accordingly, the insertion opening for thecartridge formed in the front side of the tray 2 comes to the same levelas the insertion inlet 71 formed in the front panel 70 disposed in frontof the chassis 1.

From this state, when the disk cartridge 55 is inserted into the tray 2,the levers 25 and 34 enter into the openings 58 and 59 of the shutter57, respectively, so that the shutter 57 is gradually opened accordingto the insertion motion of the cartridge. On the middle of the insertionmotion of the cartridge into the tray 2, the latch pin 24c enters intothe oval hole 38 of the lever 25 through the cut away opening 39 formedcontinuous to the hole 38 of the lever 25. When the lever 25 is furthermoved according as the cartridge 55 is further inserted toward therearmost side of the tray 2, the latch pin 24c is pushed by the lever 25so that the latch plate 24b is rotated in the clockwise directionagainst the bias force of the latch spring 24f.

Due to this function, at the time when the lever 25 is moved to the rearend position so that the shutter 57 is completely opened, as illustratedby solid lines in FIG. 3, the latch pin 24c is moved to an end of theoval hole 38 and the latch roller 24e is disengaged from the recess 24dof the carrier 3. Therefore, the eject springs 22 and 23 act on thecarrier 3 so that the carrier 3 is forced to move in the ejectingdirection toward the front side of the unit. Also, in this state, thebias force which acts upon the levers 25 and 34 is made unenforceable onthe levers due to the function of the latch mechanism 24.

As a result of the series of function as mentioned above, as illustratedby dash-two-dot lines in FIG. 4, the cams 4, 5, 6 and 7 rotate in theclockwise directions since the axles 4a, 5a, 6a and 7a of the cams 4, 5,6 and 7 are forced to move in the cartridge ejecting direction accordingas the carrier 3 moves.

As a result, the axles 4a, 5a, 6a and 7a of the cams 4, 5, 6 and 7 aremoved lowermost position thereof so that the tray 2 descends to theposition for loading the disk drive unit.

Also, in this state, the functioning surface of the magnetic head 40 ispositioned in the vicinity of the recording surface of the magneto-opticdisk (not shown) housed in the disk cartridge 55.

When the disk cartridge 55 is inserted in that way mentioned above, thecarrier 3 is shifted in the ejecting direction toward front side of theunit and the tray 2 is moved arching downward along a circular arc sothat the disk cartridge 55 is aligned with a predetermined position.

Next, the operation of ejecting the disk cartridge is described below.

When the disk cartridge 55 is to be ejected from the drive unit, theoperator presses an eject button (described later) so that the eject pin14 is moved in the cartridge insertion direction toward the rear side ofthe unit by the eject mechanism (described later) in cooperation withthe eject button. Thereby, the carrier 3 is moved in the cartridgeinsertion direction against the force of the eject springs 22 and 23.According as the carrier 3 moves in the insertion direction, the cams 4,5, 6 and 7 are rotated in the counterclockwise in FIG. 4 so that thetray 2 ascends gradually.

On the other hand, the latch plate 24b of the latch mechanism 24 isbiased to rotate counterclockwise by the latch spring 24f. Therefore,when the carrier 3 moves and comes to the position where the recess 24dformed in the carrier 3 faces to the latch roller 24e, the roller 24efalls into the recess 24d.

At the same time when the roller 24e is caught into the recess 24d, thelatch plate 24b is rotated so that the latch pin 24c pushes the lever 25and that the pin 24c disengages from the oval hole 38 of the lever 25.

Accordingly, in the state wherein the tray 2 is moved to the uppermostposition thereof, the levers 25 and 34 and the latch mechanism 24 applyforce on the disk cartridge 55 so that the cartridge 55 is pushed out ofthe tray 2 and that a part of the cartridge 55 projects from theinsertion inlet 71 formed in the front panel 70. Thereby it becomespossible to draw the cartridge 55 out of the tray 2.

As mentioned above, the carrier 3 reciprocates and simultaneouslytherewith the tray 2 moves upward or downward along the circular arctrail in accordance with the movement of the carrier 3 so that thecartridge 55 is loaded or unloaded.

Also, in accordance with this particular embodiment of the presentinvention mentioned above, tray 2 descends drawing the cartridge 55toward the rear side of the unit, which makes it possible to install thecartridge 55 in the drive unit simply by pushing the cartridge 55 intothe inlet 71. That is, it becomes unnecessary to push the cartridge 55by a finger until the cartridge 55 comes to the rear end of the insideof the disk drive unit.

FIGS. 5a and 5b illustrate an example of the eject mechanism inaccordance with the present invention.

In the drawings, the eject mechanism comprises a plate 75 on which aneject motor 76 is mounted. A worm 77 is installed on the output shaft ofthe motor 76. The worm 77 engages with a worm wheel 79 which isrotatably installed on a pin 78 mounted on the plate 75.

A male engagement member 82 is secured to the upper surface of the wormwheel 79 coaxially therewith and rotatable about the pin 78. Theengagement member 82 engages with a female engagement member 81 whichprojects downward from the chassis 1 through a hole 15. The member 81 isformed as an integral structure with a cam 80 and rotates coaxiallytherewith. Also, the plate 75 is secured to the under side of thechassis 1 by means of screws.

In accordance with the structure mentioned above, when the eject motor76 is driven to rotate, the rotational force thereof is transmitted tothe cam 80 through the worm 77, worm wheel 79, and the engagementmembers 81 and 82 so that the cam 80 rotates in the same direction asthe worm wheel 79.

Next, in the FIGS. 14a and 14b, a protrusion 791 mounted on a lowerportion of the worm wheel 79 pushes a lever of a switch to thereby stopthe worm wheel 79 in a predetermined position. In this moment, theprotrusion 791 and the cam 80 has a particular positional relationshiptherebetween. When the engagement member 81 of the cam 80 and theengagement member 82 are engaged with each other, they can be engaged intwo directions. However, one of the two directions of the engagementwill cause to disturb an operation of the eject pin 14. Therefore, asshown in FIG. 14c, in order to avoid such a disturbance, widths (C, D)of notches 821 of the engagement member 82 are made different from eachother so that the cam 80 and the worm wheel 79 are engaged with eachother only in a desired one direction.

Next, the function of the cam 80 is described with reference to FIGS. 6ato 6d below.

In a state wherein the disk cartridge 55 is not installed in the driveunit, as illustrated by the solid line in FIG. 6a, the eject pin 14 ofthe carrier 3 is positioned at the rearmost position in the anti-ejectdirection apart from the cam 80 as mentioned above. From this state,when the disk cartridge 55 is inserted, the carrier 3 is moved towardthe front side of the unit as mentioned above so that the pin 14 alsomoves toward the front side of the unit and comes close to the cam 80.Finally, the pin 14 moves to the position where the pin abuts againstthe cam 80, as illustrated by dash line in FIG. 6a.

When the cartridge is to be ejected, according to the command signal toeject the cartridge, the motor 76 is driven to rotate so that the cam 80is rotated clockwise from the state of FIG. 6b. Thereby, the pin 14 isgradually shifted toward the rear side of the unit along with thecarrier 3 in accordance with the ejecting function thereof as mentionedabove (FIGS. 6c and 6d).

Finally, immediately before the cam 80 is rotated for one turn when thepin 14 comes to the predetermined position in the cartridge ejectingdirection, the disk cartridge is ejected from the unit as mentionedabove.

When the cam 80 is rotated for one turn, the mechanism returns to theinitial state.

As mentioned above, the cartridge ejecting operation can be achieved byrotating the cam 80 for one turn by the eject motor 76.

Also, in this case, the clearance or gap between the inside rim of thehole 15 and the engagement member 81 penetrating through the hole 15 isvery small, so that almost no outer air can flow into the chassis of theunit through the gap formed around the engagement member 81 whichconstitutes the axle of the cam 80.

In this case, the optical disk drive unit is provided with a cam 80having such a shape that an increasing rate of a radius of a basiccircle of the cam 80 with respect to a rotational angle thereof changes(FIG. 16c), while conventionally, the increasing ratio thereof isconstant (FIG. 16a). Thereby, a load applied to the eject motor 76 isdispersed, and a life duration of the eject motor 76 can be prolonged.In concrete, as shown in FIG. 15, the relationship α>β is formed inwhich the radius increasing ratio between the angle 0 and the angle A₁is dr/dθ=α, and that between the angle A₁ and the A₂ is dr/dθ=β.

The reason therefor is as below. A load of a loading, namely a force forenabling a pin 14 to move increases in the latter half of a movingdistance of the pin until an ejection of the cartridge, in this loadingsystem. Therefore, when the cam has such an outer configuration that thevalue of dr/dθ decreases in the latter half of the angular displacementof the cam, the load applied to the eject motor 76 can be uniformed, theload of the eject motor 76 can be decreased, and a time used for theejection of the cartridge can be shortened (FIGS. 16b and 16d). This isbecause when an electric current flowing in the eject motor 76 is small,the load applied to the eject motor 76 decreases and therefore the lifeduration of the eject motor 76 is prolonged,

FIG. 16e is a view of an example for showing a change of the load of thesimplified loading system with respect to a loading stroke. The cam hassuch a configuration that the angular displacement amount to the pointA₁ is large while that beyond the point A₁ is small.

Also, in accordance with the arrangement mentioned above, thetransmission means for the eject mechanism is disposed outside of thechassis 1. Therefore, the dusts generated due to the engagement betweenthe worm 77 and the worm wheel 79, for instance, can be prevented fromentering into the chassis 1.

FIG. 7 illustrates an example of the sealing enclosure construction forhousing the disk drive unit in accordance with an embodiment of thepresent invention.

In the drawing, a chassis cover 85 is depicted being formed in a shapewherein the lower rim portion of the cover 85 abuts against the upperrim portion of the chassis 1 and wherein the cover 85 is secured to thechassis 1 by a screw 86 at the rear end portion of the chassis 1. Also,in the front face of the chassis cover 85 is formed an insertion inlet87 for receiving a disk cartridge which is to be inserted into the driveunit. An urged lid 88 for the inlet 87 is disposed inside the inlet 87in a state of being biased to close the opening of the inlet androtatable to open and close the inlet.

Small projections 89, 90 are formed in both side ends of the inletmember 87. Only one of the projections 90 is illustrated in FIG. 7. Theprojections 90 of the inlet member side fit into small holes 91 and 92formed in both right and left ends of the front edge of the chassis 1.The width of the lid 88 disposed in front of the chassis 1 is the sameas or slightly smaller than the outer size of the disk cartridge 55.

Also, the inlet 87 is formed in such a shape that the inlet surroundsthe whole of the outer surface of the disk cartridge 55 and that thewidth of the inlet is slightly larger than the outer width of the diskcartridge 55 and height of the inlet is about the same as the thicknessof the disk cartridge 55 so that the upper and lower surfaces of thedisk cartridge 55 come in slight contact with the upper and lowermembers which constitute the inlet.

A recessed step 93 is formed under the inlet 87. A front wall 94 isarranged in the front side of the chassis 1. The vertical front sidesurface of the step 93 abuts against the vertical inner side surface ofthe front wall 94. The height of the front wall 94 is slightly shorterthan the leveling pins 8, 9, 10 and 11 (FIG. 1).

Also, each of the side plates 1a and 1b of the chassis 1 (FIG. 1) has aprojecting step formed on its upper surface which step mates with arecessed step formed on the lower surface of each side plate of thechassis cover 85 so that the sealing tightness between the chassis andthe cover is enhanced. This structure is illustrated in FIG. 8 whichshows the side plate 1a of the chassis having the step 1aa projectingfrom the upper surface of the plate 1a formed in such a way that thestep 1aa is received by and mates with the recessed step 85a formed inthe lower surface of the side plate of the cover 85.

In accordance with the above mentioned way of arrangement, the chassiscover 85 is attached to the chassis 1 and the inlet 87 for insertion andejection of the cartridge is closed by the lid 88 so that the inside ofthe chassis 1 is sealingly closed from outside.

Also, the chassis 1 is mounted on and secured to a frame 95 through padsor vibroisolating rubbers 96, 97, 98 and 99.

Also, a front panel 70 is attached to the front surface of the frame 95.Vent slots 100 for intaking outer air are formed in the lower portion ofthe panel 70. Also, an eject button 101 is arranged on the panel 70.

FIG. 9 illustrates an access mechanism for read/write data on and fromthe magneto-optic disk assembled in the chassis 1. The mechanismarranged in the chassis 1 comprises a spindle motor 102 for driving themagneto-optic disk to rotate, a turn table 104 installed on the shaft103 of the motor 102 for mounting the disk thereon, an optical pickupdevice 105, seek motors 106 and 107 for driving the optical pickupdevice to move and a linear encoder 108 for detecting the schematicposition of the optical pickup.

A flexible printed wiring board 109 is disposed on the optical pick updevice. Necessary circuits for driving the optical pickup 105, seekmotors 106 and 107 and the linear encoder 108 are arranged on theprinted wiring board 109. The wirings of the flexible printed wiringboard 109 are connected to pins of a connector 111 which projects intothe chassis 1 from underside thereof through a hole 110 formed in thebottom plate of the chassis 1, as illustrated in FIG. 10.

The connector 111 is connected to a control board 112 disposed under thechassis 1. Also, the hole 110 is covered and closed by the flexibleprinted wiring board 109 so that sealing tightness of the hole 109 israised.

The drive circuit and control circuit for the motors disposed in thechassis 1 are mounted on a wiring board 116 disposed in a space betweenthe rear end of the chassis 1 and the rear end of the frame 95. To thiscircuit board 116 is connected a heat radiation plate 117 attached tothe rear end of the frame 95 so as to radiate the heat generated fromthe parts mounted on the board 116.

Also, in a state wherein the disk cartridge 55 is installed in the unit,the under surface of the trailing end of the disk cartridge 55 comes inslight contact with the upper surface of the front wall 94 of thechassis 1. In this state, the disk cartridge 55 comes in contact withthe lower member 87a of the inlet 87 formed in the chassis cover 85 sothat the lower part of the cartridge is sealed. Also, the lower edge ofthe lid 88 comes in contact with the upper surface of the disk cartridge55 so that the upper part of the cartridge is sealed. Further, bothsides of the disk cartridge 55 come in contact with the inner side wallof the inlet 87 so that the both side parts of the cartridge are sealed.

As mentioned above, even in the case where the disk cartridge 55 isinserted in the unit, the sealing tightness between the cartridge 55 andthe chassis 1 is reliably maintained so that the outer air is almostprevented from entering into the chassis 1 through the gap between thechassis 1 and the cartridge 55.

Besides, the impact force which acts upon the chassis 1 is absorbed bythe vibroisolating rubbers 96, 97, 98 and 99, which keeps the gapbetween the chassis 1 and the members surrounding the chassis closed sothat the sealing tightness of the chassis is maintained being unchangedeven when an impact force acts upon the chassis.

In accordance with the above mentioned arrangement of the enclosure fordisk cartridge, the access mechanism housed in the chassis 1 is alwayssealingly enclosed in the chassis and discommunicated from the outsideof the chassis. Therefore, even in the event where the cooling air isventilated into the frame 95, the outer air is essentially preventedfrom entering into the access mechanism as a result of which it becomespossible to avoid the event that dusts included in the air stick to theoptical parts of the pickup device.

Further, the heat generating sources such as the drive circuit and thecontrol circuit for the access mechanism are assembled on the circuitboard 116 disposed at the rear end portion of the frame 95 so that theheat is prevented from being accumulated in the chassis 1 to a certaindegrees. Also, the heat from inside of the chassis 1 is radiated tooutside of the chassis 1 through the outer surface of the chassis 1 andthe its cover 85, which makes it possible to keep the temperature in thechassis 1 within an allowance range for the access mechanism and themagneto-optic disk.

it is to be noted that by constituting the chassis 1 from die castingmaterial, it becomes possible to raise the accuracy of size of each partof the chassis, which further enables to raise the sealing tightness ofthe chassis 1.

It is also to be noted that by constituting the chassis cover 85 fromplastic material, it becomes possible to easily realize a complicatedshape, which makes it possible to obtain a high sealing tightnesswithout using a special sealing member. Also, the chassis cover 85 iseasily attached to the chassis 1 as well and the lid 88 is also easilyattached to the chassis cover 85.

FIG. 11 illustrates an example of the block diagram of the controlsystem for the disk drive unit in accordance with the present invention.

In the drawing is represented a control unit 120 which transmits andexchanges various data between the host device so as to control thefunction of the magneto-optic disk device. The control unit 120 alsocontrols the functions of the eject motor 6, the spindle motor 102, thephoto pickup device 105 and the seek motors 106 and 107.

Numeral 121 designates a group of sensors such as a write protect sensor48, and media mark sensors 45, 46 and 47. The detected signals outputfrom the sensors 121 are transmitted to the control unit 120. The on/ofsignal output from the eject switch 122 operated in cooperation with theeject button 101 is also transmitted to the control unit 120. Further,The detection signal output from the position sensor 123 which detectsone turn of the cam 80 is also transmitted to the control unit 120.

FIG. 12 illustrates a flow chart of the sequence executed by the controlunit 120 at the time when the eject switch 122 is turned on by pressingthe eject button 101.

First, whether the spindle motor 102 is stopped or not is checked instep 201. If the check result is NO, the spindle motor 102 isdeenergized to stop (step 202).

When the motor 102 is stopped in such a way, the eject motor 76 isdriven to rotate until the position sensor 123 outputs the detectionsignal (step 203).

It is to be noted that, in accordance with the sealing arrangement ofthe embodiment mentioned above, the gap between the shaft (engagementmember) 81 of the cam 80 and the inside wall of the hole 15 formed inthe chassis 1 is not completely sealed. However, instead of such anarrangement, to achieve a complete sealing at this portion, it may bepossible to arrange an oilless type metal bearing 210 for the shaft 81which bearing fits into the hole 15, as illustrated in FIG. 13a. Orotherwise, it also may possible to arrange a sealing type ball bearing211 for the shaft 81 which bearing fits into the hole 15, as illustratedin FIG. 13b.

Further, instead of those arrangements mentioned above, it also maypossible to arrange the sealing structure in such a way that a wall 15ais formed on the chassis floor member surrounding the hole 15 and that asealing wall 80a is formed hanging from the cam 80 and covering the wall15a from outer side thereof, as illustrated in FIG. 13c. In accordancewith this arrangement, the gap between the wall 15a and the sealingmember 80 is cranked and constitutes a labyrinth seal structure so thatit becomes possible to almost completely prevent the entrance of theouter air through the gap into the chassis.

It is to be noted that in accordance with the embodiment mentionedabove, the invention is applied to a magneto-optic disk drive unit.However, the present invention can be applied to an optical disk driveunit as well.

It is also to be noted that in accordance with the embodiment mentionedabove, the cartridge insertion inlet portion of the chassis cover isformed in such a shape that the inlet member surrounds the entiresurface of the disk cartridge to be inserted. However, the lower sidemember of the inlet can be deleted without impairing the effect of thepresent invention.

As mentioned above, in accordance with the present invention, the drivemeans for driving the eject pin is disposed outside of the sealingenclosure unit housing the disk drive arrangement, which makes itpossible to effectively prevent the entrance of the dusts or otherminute particles generated from the driving mechanism into the enclosureunit. Also, in accordance with the present invention, the arrangement ismade to close the gap between the inner side wall of the hole formed inthe chassis and the linkage member which is disposed between the cam andthe cam drive means and penetrates through the hole to interconnect thecam and the drive means together, which makes it possible to reliablyprevent the entrance of dusts or other particles into the drive unitenclosure through the gap.

Many widely different embodiments of the present invention may beconstructed without departing from the spirit and scope of the presentinvention. It should be understood that the present invention is notlimited to the specific embodiments described in the specification,except as defined in the appended claims.

What is claimed is:
 1. An optical disk drive unit for loading a diskcartridge which houses a disk-shaped recording medium at a predeterminedposition in the unit and ejecting the loaded disk cartridge from theunit as well, said optical disk drive unit comprising: a sealingenclosure which sealingly encloses said recording medium and an accessmechanism for writing/reading data on and from said recording mediumfrom exterior in a state where said disk cartridge is installed in theunit; an input means for inputting a command signal to eject said loadeddisk cartridge from the unit; an eject means for ejecting said diskcartridge from the unit; a pin for moving and arranging said eject meansto a state for starting its ejecting function; a cam member which isarranged in such a way that said cam member is disengaged from said pinwhen said disk cartridge is being unloaded from the unit and that saidcam member contacts said pin to start said ejecting function by saideject means when said disk cartridge is being loaded in the unit so thatby rotating said cam member, said ejecting function can be conducted; acam drive means for driving said cam member to rotate which drive meansis disposed outside of said sealing enclosure; a linkage means forconnecting a rotational shaft of said cam drive means to said cam memberwhich linkage means is disposed penetrating through a hole formed insaid sealing enclosure; and a control means for controlling said cammember in such a way that upon receipt of said command signal to ejectsaid disk cartridge transmitted from said input means, said cam drivemeans is driven to rotate said cam member until said disk cartridge isejected; wherein a sealing type bearing means is disposed between saidlinkage means and said hole through which said linkage means penetratessaid enclosure from outside to inside thereof.
 2. An optical disk driveunit according to claim 1, wherein a wall member is disposed surroundingsaid hole and wherein an enclosing member which covers said wall memberfrom outer side thereof is disposed on said cam member.
 3. An opticaldisk drive unit according to claim 2, wherein a labyrinth seal structureis constituted from said wall member and said enclosing membersurrounding said wall member.
 4. An optical disk drive unit according toclaim 1, wherein said sealing enclosure is composed of a chassisconstituting a lower part of said enclosure and a chassis coverconstituting an upper part of said enclosure, and wherein each of theside plates of said chassis has a projecting step formed on its uppersurface which mates with a recessed step formed on the lower surface ofeach side plate of said chassis cover so that said chassis and cover arecombined together through said projecting steps mating together alongsaid edges thereof.
 5. An optical disk drive unit according to claim 4,wherein said chassis has a hole, wherein a cam member is disposed abovesaid hole within said chassis, and wherein a linkage member whichconstitutes a rotational shaft of said cam member is connected to aneject motor disposed outside of said chassis through said hole.
 6. Anoptical disk drive unit according to claim 5, wherein said linkagemember engages with a male engagement member having at least two notchesdifferent from each other in width, and wherein said male engagementmember transmits a rotational force to said linkage member.
 7. Anoptical disk drive unit according to claim 5, wherein said cam memberhas an outer configuration such that an increasing ratio of a radius ofa basic circle of said cam member to a rotational angle of said cammember is not constant.
 8. An optical disk drive unit according to claim4, wherein said chassis cover has a disk cartridge insertion inletformed in the front side thereof, said inlet being covered by an urgedlid which is biased to close the opening of the inlet and rotatable toopen and close the inlet, and which has a lower edge which comes incontact with an upper surface of the cartridge when the disk cartridgeis inserted into said enclosure through said inlet.
 9. An optical diskdrive unit for loading a disk cartridge which houses a disk-shapedrecording medium at a predetermined position in the unit and ejectingthe loaded disk cartridge from the unit as well, said optical disk driveunit comprising: a sealing enclosure which sealingly encloses saidrecording medium and an access mechanism for writing/reading data on andfrom said recording medium from exterior in a state where said diskcartridge is installed in the unit, wherein said sealing enclosure iscomposed of a chassis constituting a lower part of said enclosure and achassis cover constituting an upper part of said enclosure, and whereineach of the side plates of said chassis has a projecting step formed onits upper surface which mates with a recessed step formed on the lowersurface of each side plate of said chassis cover so that said chassisand cover are combined together through said projecting steps matingtogether through said projecting steps mating together along said edgesthereof; an input means for inputting a command signal to eject saidloaded disk cartridge from the unit; an eject means for ejecting saiddisk cartridge from the unit; a pin for moving and arranging said ejectmeans to a state for starting its ejecting function; a cam member whichis arranged in such a way that said cam member is disengaged from saidpin when said disk cartridge is unloaded from the unit and that said cammember contacts said pin to start said ejecting function by said ejectmeans when said disk cartridge is loaded in the unit so that by rotatingsaid cam member, said ejecting function can be conducted; a cam drivemeans for driving said cam member to rotate which drive means isdisposed outside of said sealing enclosure; a linkage means forconnecting a rotational shaft of said cam drive means to said cam memberwhich linkage means is disposed penetrating through a hole formed insaid sealing enclosure for transmitting a driving force from the camdrive means to the cam member by rotation thereof; a sealing typebearing means is disposed between said linkage means and said hole; anda control means for controlling said cam member in such a way that uponreceipt of said command signal to eject said disk cartridge which housesa disk-shaped recording medium at a predetermined transmitted from saidinput means, said cam drive means is driven to rotate said cam memberuntil said disk cartridge is ejected.
 10. An optical disk drive unit forloading a disk cartridge which houses a disk-shaped recording medium ata predetermined position in the unit and ejecting the loaded diskcartridge from the unit as well, said optical disk drive unitcomprising: a sealing enclosure which sealingly encloses said recordingmedium and an access mechanism for writing/reading data on and from saidrecording medium from exterior in a state where said disk cartridge isinstalled in the unit; an input means for inputting a command signal toeject said loaded disk cartridge from the unit; an eject means forejecting said disk cartridge from the unit; a pin for moving andarranging said eject means to a state for starting its ejectingfunction; a cam member which is arranged in such a way that said cammember is disengaged from said pin when said disk cartridge is unloadedfrom the unit end that said cam member is contacted by said pin to startsaid ejecting function by said eject means when said disk cartridge isloaded in the unit so that by rotating said cam member said ejectingfunction can be conducted; a cam drive means for driving said cam memberto rotate which drive means is disposed outside of said sealingenclosure; a linkage means for connecting a rotational shaft of said camdrive means to said cam member which linkage means is disposedpenetrating through a hole formed in said sealing enclosure; and asealing type bearing means is disposed between said linkage means andsaid hole; a wall member is disposed surrounding said hole and whereinan enclosing member which covers said wall member from an outer sidethereof is disposed on said cam member; a labyrinth seal structure isconstituted from said wall member and said enclosing member surroundingsaid wall member; and a control means for controlling said cam member insuch a way that upon receipt of said command signal to eject said diskcartridge transmitted from said input means, said cam drive means isdriven to rotate said cam member until said disk cartridge is ejected.11. An optical disk drive unit according to claim 10, wherein saidsealing enclosure is composed of a chassis constituting a lower part ofsaid enclosure and a chassis cover constituting an upper part of saidenclosure, and wherein each of the side plates of said chassis has aprojecting step formed on its upper surface which mates with a recessedstep formed on the lower surface of each side plate of said chassiscover so that said chassis and cover are combined together through saidprojecting steps mating together along said edges thereof; said chassishas a hole, said cam member is disposed above said hole within saidchassis, and said linkage means which constitutes a rotational shaft ofsaid cam member is connected to an eject motor disposed outside of saidchassis through said hole; said chassis cover has a disk cartridgeinsertion inlet formed in the front side thereof, said inlet beingcovered by an urged lid which is biased to close the opening of theinlet and ratable to open and close the inlet, and has a lower edgewhich comes in contact with an upper surface of the cartridge when thedisk cartridge is inserted into said enclosure through said inlet; saidlinkage member engages with a male engagement member having at least twonotches different from each other in width, said male engagement membertransmitting a rotational force to said linkage member; and said cammember has such an outer configuration that an increasing ratio of aradius of a basic circle of said cam member to a rotational angle ofsaid member is not constant.
 12. An optical disk drive unit for loadinga disk cartridge which houses a disk-shaped recording medium at apredetermined position in the unit and ejecting the loaded diskcartridge from the unit as well, said optical disk drive unitcomprising: a sealing enclosure which sealingly encloses said recordingmedium and an access mechanism for writing/reading data on and from saidrecording medium from exterior in a state where said disk cartridge isinstalled in the unit; an input means for inputting a command signal toeject said loaded disk cartridge from the unit; an eject means forejecting said disk cartridge from the unit; a pin for moving andarranging said eject means to a state for starting its ejectingfunction; a cam member, provided within the sealing enclosure and whichis arranged in such a way that said cam member is disengaged from saidpin when said disk cartridge is unloaded from the unit and that said cammember contacts said pin to start said ejecting function by said ejectmeans when said disk cartridge is loaded in the unit so that by rotatingsaid cam member, said ejecting function can be conducted; a cam drivemeans for generating a rotational driving force, said cam drive meansbeing disposed outside of said sealing enclosure; a linkage means forconnecting a rotational shaft of said cam drive means to said cammember, said linkage means being disposed rotatably so as to penetratethrough a hole formed in said sealing enclosure for transmitting therotational driving force of said cam drive means to said cam member,said hole having a diameter substantially equal to that of said linkagemeans, said hole and said linkage means substantially forming a portionof said sealing enclosure; and a control means for controlling said cammember in such a way that upon receipt of said command signal to ejectsaid disk cartridge transmitted from said input means, said cam drivemeans is driven to rotate said cam member until said disk cartridge isejected.
 13. An optical disk drive unit according to claim 12, wherein asealing means is disposed between said linkage means and said holethrough which said linkage means penetrates said sealing enclosure fromoutside to inside thereof.
 14. An optical disk drive unit according toclaim 12, wherein a sealing type bearing means is disposed between saidlinkage means and said hole through which said linkage means penetratessaid sealing enclosure from outside to inside thereof.
 15. An opticaldisk drive unit according to claim 12, wherein a wall member is disposedsurrounding said hole and wherein an enclosing member which covers saidwall member from an outer side thereof is disposed on said cam member.16. An optical disk drive unit according to claim 15, wherein alabyrinth seal structure is constituted from said wall member and saidenclosing member surrounding said wall member.
 17. An optical disk driveunit according to claim 12, wherein said sealing enclosure is composedof a chassis constituting a lower part of said sealing enclosure and achassis cover constituting an upper part of said sealing enclosure, andwherein each of the side plates of said chassis has a projecting stepformed on its upper surface which mates with a recessed step formed onthe lower surface of each side plate of said chassis cover so that saidchassis and said chassis cover are combined together through saidprojecting steps mating together along said edges thereof.
 18. Anoptical disk drive unit according to claim 17, wherein said chassis hasa hole, wherein a cam member is disposed above said hole within saidchassis, and wherein a linkage member which constitutes a rotationalshaft of said cam member is connected to an eject motor disposed outsideof said chassis through said hole.
 19. An optical disk drive unitaccording to claim 18, wherein said linkage member engages with a maleengagement member having at least two notches different from each otherin width, and wherein said male engagement member transmits a rotationalforce to said linkage member.
 20. An optical disk drive unit accordingto claim 18, wherein said cam member has an outer configuration suchthat an increasing ratio of a radius of a basic circle of said cammember to a rotational angle of said cam member is not constant.
 21. Anoptical disk drive unit according to claim 17, wherein said chassiscover has a disk cartridge insertion inlet formed in the front sidethereof, said inlet being covered by an urged lid which is biased toclose the opening of the inlet and rotatable to open and close theinlet, and which has a lower edge which comes in contact with an uppersurface of the cartridge when the disk cartridge is inserted into saidsealing enclosure through said inlet.